Various kinds of electronic measurement instruments have many functions as a result of the increasing operational complexity of such instruments. However, not all of the functions are needed for simple measurements, and the necessary functions are selected in accordance with level of measurement complexity, i.e., the operation level. The number of available functions is generally dependent on the operation level, i.e., more functions are available for a high operation level.
Conventional measurement instruments include many function keys or switches for making selections or setting values with respect to the functions, or they include numeric keys for making selections or setting values by reference to displayed menus. When operating the instruments, the operator is required to make selections or set values with respect to all the functions, even if he does not need some of the functions. He may select "don't care" with respect to an unnecessary function. These unnecessary setting operations are troublesome. Especially if the operator is not skilled, it is difficult for him to operate a measurement instrument having many functions.